Cool (pipe) runnings

Pipe fabricator changes approach to bobsled run fabrication

A pipe fabricator finds a new way to fabricate and assemble a bobsled run for the 2010 Winter Olympics in Vancouver.

Figure 1A bobsledder tests the track at the Whistler Sliding Centre, built for the 2010 Winter Olympics, Photo courtesy of the Vancouver Organizing Committee; David McColm, photographer.

Late last year several Russian engineers visited a pipe fabrication shop on Annacis Island, Delta, B.C., just outside Vancouver. No pictures were allowed, but the team was able to pore over some original plans and drawings. Their aim: to discover how Ideal Welders Ltd. saved the Vancouver Olympics Organizing Committee more than $1 million.

Jim Longo, Ideal Welders president, didn't hesitate to share. The shop was helping a Russian Olympic organization, which had successfully won a bid for the 2014 Winter Games in Sochi, on the eastern coast of the Black Sea, at the foot of the Caucasus Mountains.

The drawings the Russians pored over detailed a new way to build a bobsled run, now ready for the 2010 games (see Figure 1). Traditional track projects have called for massive on-site construction, and the specifications for the Vancouver run looked no different: more than 1.1 million pounds of piping, including 71 miles of 1-inch pipe requiring some 27,000 pressurized pipe welds made with shielded metal arc (stick), gas metal arc (MIG), and gas tungsten arc (TIG) welding; and, not least, more than 800 pipe bends of varying diameters and radii. All pipe was seamless Schedule 40, SA 106 Grade B material, ranging in diameter from 1 to 16 in. And all this would be built into a 1.7-kilometer (1-mile) track that would wind its way down a rocky slope in Whistler, a mountainous resort town north of Vancouver.

In the past all this called for some 60,000 labor-hours of on-site work. But Longo knew Whistler. His family had spent weekends there for 25 years. He and his staff knew there was a better way—and that way helped Ideal Welders' bid come in well below competing bids.

The Anatomy of a Bobsled Run

Bobsled runs aren't as simple as they look. The run itself sits on 12- by 12-foot concrete risers. Attached to this are two 10-in. I beams, one vertical and one horizontal. On top of this sits the track, consisting of pipe, mesh, rebar, concrete, and, ultimately, several inches of ice (see Figure 2).

Whistler's bobsled run is really 28 separate "ice rinks," linear instead of round, each with its own cooling system. Each section, called vaporizer sections, uses pipes to carry chilled ammonia from supply pipelines underneath the track (seeFigure 3). These pipes are from 6 in. to 16 in. in diameter, which feed into a series of 1-in. pipe, on top of which go a mesh, rebar, and concrete. Throughout most of the run, the track has a C-shaped cross section about 5 ft. wide and with varying heights, from about 5 ft. high on the straightaways to 20 ft. or more around the track's 10 turns. The entire track has between 80 and 100 of these 1-in. pipes spaced 2 in. apart.

The entire pressurized piping system is designed and certified to the ASME Section IX code. In a refrigeration building sit two large storage vessels. From these, ammonia travels through various chillers and compressors. It then feeds into supply pipes under the track, up into the 1-in. pipe inside the track sections, through return lines, and back to the refrigeration building for rechilling. The chilled ammonia, of course, is how several inches of ice stay frozen. Along the entire track also are about 120 control stations—modules of piping and valves about the size of a pickup truck—to monitor the ammonia flow.

To be sure, this was no small job.

Rethinking the Run

Ideal Welders has kept its pipe fabrication focus for 35 years, serving industries such as pulp and paper and petrochemical throughout North America. Among the company's 100 employees are experienced pipe welders with years of field experience (see Figure 4).

With this background, Longo knew his company could tackle the bobsled job, but to win the bid he and his managers—Vice President of Operations Dale Hamil, Shop Foreman Pat Little, Project Engineer Misha Slavkovic, Senior Project Estimator Jim Murphy, Field Superintendent Dan Moosmann, and Piping Detailer Lead Jose Lam—put their heads together to find a better way.

Figure 2Click on image to view larger The track consists of pipe, mesh, rebar, concrete, and ultimatley, several inches of ice.

What traditionally has made bobsled pipe fabrication so expensive has been the 60,000 hours of on-site work, with fabricators buying 20-ft. to 60-ft. sections, then cutting, bending, and welding them in the field as the run takes shape. But the staff knew Whistler. It's mountainous, the weather unpredictable. So, the managers asked, what if they could prefabricate sections on the fab shop floor—a controllable environment? It never snows inside the shop.

"We didn't want to put the 60,000 hours of work that historically has always been done in the field," Longo said. "Instead, we ended up putting 45,000 hours in the shop and only 15,000 hours in the field."

They did this by, as Longo put it, "making the job truckable."

The shop has experience with complex prefabrication. Fabricated modules, or skid packages, consisting of prefabricated pipe assemblies delivered by flatbed truck to oil and chemical processing plants, have been an Ideal Welders specialty for years. What made the bobsled job unique were the sheer volume of pipe and, most challenging, an unpredictable construction schedule. With so many contractors involved on a mountainside project, schedule changes were bound to happen.

Making It Truckable

Company managers had to overcome two primary hurdles. First, they knew they needed in-house production that could deliver sections on demand. Second, the company needed to deliver these sections in such a way as to minimize on-site installation time.

Shop floor fabrication had to be quick and flexible. The shop divided track fabrication into sections between 40 and 50 ft. long, short enough to fit on a flatbed truck. Each track module involved welding and, most notably, a host of repetitive bends—800 of them in all. Although the bend radii changed between sections, the basic operation didn't. The company used a few small Greenlee electric benders for the header pipe bends in the supply lines. But what about the 71 miles of 1-in. pipe?

Here, shop supervisors took a look at their plate roller.

"We actually took a small set of plate rolls and machined grooves in them to accommodate the 1-inch pipe," Longo explained. That way, workers could set up multiple pipes across the width of the plate roll and bend them all at once to programmed angles.

This greatly reduced bending time, but one issue remained: how to transport these somewhat flimsy sections of 80 to 100 pipes ganged together in the shape of the track? These kinds of transportation challenges have forced pipe fabricators working on previous bobsled runs to do what's always been done: bring all fabrication on-site.

For a solution, Ideal Welders contracted with a company that made custom plastic foam blocks for packaging houses. Ideal Welders had several hundred of these blocks made, cut to the shape of the track, about 4 ft. across and 2 ft. wide, then inserted and strapped them to the pipe-frame sections for shipping. All told, flatbed trucks made the trip to the Whistler mountaintop about 150 times.

"When it finally got to the field, we could lift and place the section with a crane," Longo explained (see Figures 5-9).

Once the sections made it to the mountaintop, operations still weren't business as usual. Traditionally, bobsled runs have required thousands of tack welds to secure spacer bars holding the 1-in. pipes in place, 2 in. apart, before the mesh, rebar, and concrete were placed on top.

Recalled Longo, "We asked, ‘Why would we want to do that?'"

So the company contracted Delta, B.C.-based Brenco Industries to laser-cut scallop bars with 1-in.-dia. "scallop" spaces cut into them. Then Ideal designed spring clips, made of 4140 spring steel, that would clip to the pipe and wrap around the back of the scallop bar. Under the auspices of project engineers, the company performed tensile tests, using come-alongs to pull both scalloped and tack-welded spacer bars. "We proved to the engineers that [the scallop-bar and spring arrangement] was as good, if not better, than tack welding," he said.

Instead of tack welding over and over, on-site workers simply snapped the pipes into the spaces and held them firm with 4140 spring steel clips.

A Gold Medal Effort

In December 2007 the Vancouver Organizing Committee honored Ideal Welders for a job well done with, appropriately, a gold medal, recognizing the company for its part in a construction project that finished ahead of schedule.

It wasn't smooth sailing throughout. Like any project involving myriad contractors and unpredictable conditions, schedule changes abounded, and Ideal Welders had to be prepared to work on different sections as needed. Moreover, different steps in construction had to happen rapidly in succession. "Once the footings were in, the piping had to go in, then the mesh, then the concrete," Longo said. "Things had to happen fast."

The weather didn't cooperate either. The project, which began with initial planning work in June 2005, had been scheduled to shut down for the winter by mid-December 2006, but a major November snowstorm shut the project down early, cutting a month off the construction schedule.

In the end, all parties came through, and the entire track was completed by November 2007, a month before the first track testing. Today the entire facility, dubbed the Whistler Sliding Centre, is undergoing final tweaks for the International Bobsleigh Federation's first major event at the track in February 2009.

After that, it's on to the Olympics.

Figure 6click on image to view larger This straightaway seciton, with 1-in. piping in place, awaits the wire mesh, rebar, and concrete topping.

Tim Heston

Published In...

The Tube & Pipe Journal

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